leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity
aceda401e8
linux/drivers/spi/spi.c
Saravana Kannan 27e7db56cf
spi: Don't have controller clean up spi device before driver unbind 
When a spi device is unregistered and triggers a driver unbind, the
driver might need to access the spi device. So, don't have the
controller clean up the spi device before the driver is unbound. Clean
up the spi device after the driver is unbound.

Fixes: c7299fea67 ("spi: Fix spi device unregister flow")
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210505164734.175546-1-saravanak@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-14 13:24:56 +01:00

4290 lines
114 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
// SPI init/core code
//
// Copyright (C) 2005 David Brownell
// Copyright (C) 2008 Secret Lab Technologies Ltd.
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/clk/clk-conf.h>
#include <linux/slab.h>
#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include <linux/of_gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/property.h>
#include <linux/export.h>
#include <linux/sched/rt.h>
#include <uapi/linux/sched/types.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#include <linux/highmem.h>
#include <linux/idr.h>
#include <linux/platform_data/x86/apple.h>
#define CREATE_TRACE_POINTS
#include <trace/events/spi.h>
EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
#include "internals.h"
static DEFINE_IDR(spi_master_idr);
static void spidev_release(struct device *dev)
{
struct spi_device *spi = to_spi_device(dev);
spi_controller_put(spi->controller);
kfree(spi->driver_override);
kfree(spi);
}
static ssize_t
modalias_show(struct device *dev, struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
int len;
len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
if (len != -ENODEV)
return len;
return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
}
static DEVICE_ATTR_RO(modalias);
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *a,
const char *buf, size_t count)
{
struct spi_device *spi = to_spi_device(dev);
const char *end = memchr(buf, '\n', count);
const size_t len = end ? end - buf : count;
const char *driver_override, *old;
/* We need to keep extra room for a newline when displaying value */
if (len >= (PAGE_SIZE - 1))
return -EINVAL;
driver_override = kstrndup(buf, len, GFP_KERNEL);
if (!driver_override)
return -ENOMEM;
device_lock(dev);
old = spi->driver_override;
if (len) {
spi->driver_override = driver_override;
} else {
/* Empty string, disable driver override */
spi->driver_override = NULL;
kfree(driver_override);
}
device_unlock(dev);
kfree(old);
return count;
}
static ssize_t driver_override_show(struct device *dev,
struct device_attribute *a, char *buf)
{
const struct spi_device *spi = to_spi_device(dev);
ssize_t len;
device_lock(dev);
len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
#define SPI_STATISTICS_ATTRS(field, file) \
static ssize_t spi_controller_##field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct spi_controller *ctlr = container_of(dev, \
struct spi_controller, dev); \
return spi_statistics_##field##_show(&ctlr->statistics, buf); \
} \
static struct device_attribute dev_attr_spi_controller_##field = { \
.attr = { .name = file, .mode = 0444 }, \
.show = spi_controller_##field##_show, \
}; \
static ssize_t spi_device_##field##_show(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct spi_device *spi = to_spi_device(dev); \
return spi_statistics_##field##_show(&spi->statistics, buf); \
} \
static struct device_attribute dev_attr_spi_device_##field = { \
.attr = { .name = file, .mode = 0444 }, \
.show = spi_device_##field##_show, \
}
#define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
char *buf) \
{ \
unsigned long flags; \
ssize_t len; \
spin_lock_irqsave(&stat->lock, flags); \
len = sprintf(buf, format_string, stat->field); \
spin_unlock_irqrestore(&stat->lock, flags); \
return len; \
} \
SPI_STATISTICS_ATTRS(name, file)
#define SPI_STATISTICS_SHOW(field, format_string) \
SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
field, format_string)
SPI_STATISTICS_SHOW(messages, "%lu");
SPI_STATISTICS_SHOW(transfers, "%lu");
SPI_STATISTICS_SHOW(errors, "%lu");
SPI_STATISTICS_SHOW(timedout, "%lu");
SPI_STATISTICS_SHOW(spi_sync, "%lu");
SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
SPI_STATISTICS_SHOW(spi_async, "%lu");
SPI_STATISTICS_SHOW(bytes, "%llu");
SPI_STATISTICS_SHOW(bytes_rx, "%llu");
SPI_STATISTICS_SHOW(bytes_tx, "%llu");
#define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
"transfer_bytes_histo_" number, \
transfer_bytes_histo[index], "%lu")
SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
static struct attribute *spi_dev_attrs[] = {
&dev_attr_modalias.attr,
&dev_attr_driver_override.attr,
NULL,
};
static const struct attribute_group spi_dev_group = {
.attrs = spi_dev_attrs,
};
static struct attribute *spi_device_statistics_attrs[] = {
&dev_attr_spi_device_messages.attr,
&dev_attr_spi_device_transfers.attr,
&dev_attr_spi_device_errors.attr,
&dev_attr_spi_device_timedout.attr,
&dev_attr_spi_device_spi_sync.attr,
&dev_attr_spi_device_spi_sync_immediate.attr,
&dev_attr_spi_device_spi_async.attr,
&dev_attr_spi_device_bytes.attr,
&dev_attr_spi_device_bytes_rx.attr,
&dev_attr_spi_device_bytes_tx.attr,
&dev_attr_spi_device_transfer_bytes_histo0.attr,
&dev_attr_spi_device_transfer_bytes_histo1.attr,
&dev_attr_spi_device_transfer_bytes_histo2.attr,
&dev_attr_spi_device_transfer_bytes_histo3.attr,
&dev_attr_spi_device_transfer_bytes_histo4.attr,
&dev_attr_spi_device_transfer_bytes_histo5.attr,
&dev_attr_spi_device_transfer_bytes_histo6.attr,
&dev_attr_spi_device_transfer_bytes_histo7.attr,
&dev_attr_spi_device_transfer_bytes_histo8.attr,
&dev_attr_spi_device_transfer_bytes_histo9.attr,
&dev_attr_spi_device_transfer_bytes_histo10.attr,
&dev_attr_spi_device_transfer_bytes_histo11.attr,
&dev_attr_spi_device_transfer_bytes_histo12.attr,
&dev_attr_spi_device_transfer_bytes_histo13.attr,
&dev_attr_spi_device_transfer_bytes_histo14.attr,
&dev_attr_spi_device_transfer_bytes_histo15.attr,
&dev_attr_spi_device_transfer_bytes_histo16.attr,
&dev_attr_spi_device_transfers_split_maxsize.attr,
NULL,
};
static const struct attribute_group spi_device_statistics_group = {
.name = "statistics",
.attrs = spi_device_statistics_attrs,
};
static const struct attribute_group *spi_dev_groups[] = {
&spi_dev_group,
&spi_device_statistics_group,
NULL,
};
static struct attribute *spi_controller_statistics_attrs[] = {
&dev_attr_spi_controller_messages.attr,
&dev_attr_spi_controller_transfers.attr,
&dev_attr_spi_controller_errors.attr,
&dev_attr_spi_controller_timedout.attr,
&dev_attr_spi_controller_spi_sync.attr,
&dev_attr_spi_controller_spi_sync_immediate.attr,
&dev_attr_spi_controller_spi_async.attr,
&dev_attr_spi_controller_bytes.attr,
&dev_attr_spi_controller_bytes_rx.attr,
&dev_attr_spi_controller_bytes_tx.attr,
&dev_attr_spi_controller_transfer_bytes_histo0.attr,
&dev_attr_spi_controller_transfer_bytes_histo1.attr,
&dev_attr_spi_controller_transfer_bytes_histo2.attr,
&dev_attr_spi_controller_transfer_bytes_histo3.attr,
&dev_attr_spi_controller_transfer_bytes_histo4.attr,
&dev_attr_spi_controller_transfer_bytes_histo5.attr,
&dev_attr_spi_controller_transfer_bytes_histo6.attr,
&dev_attr_spi_controller_transfer_bytes_histo7.attr,
&dev_attr_spi_controller_transfer_bytes_histo8.attr,
&dev_attr_spi_controller_transfer_bytes_histo9.attr,
&dev_attr_spi_controller_transfer_bytes_histo10.attr,
&dev_attr_spi_controller_transfer_bytes_histo11.attr,
&dev_attr_spi_controller_transfer_bytes_histo12.attr,
&dev_attr_spi_controller_transfer_bytes_histo13.attr,
&dev_attr_spi_controller_transfer_bytes_histo14.attr,
&dev_attr_spi_controller_transfer_bytes_histo15.attr,
&dev_attr_spi_controller_transfer_bytes_histo16.attr,
&dev_attr_spi_controller_transfers_split_maxsize.attr,
NULL,
};
static const struct attribute_group spi_controller_statistics_group = {
.name = "statistics",
.attrs = spi_controller_statistics_attrs,
};
static const struct attribute_group *spi_master_groups[] = {
&spi_controller_statistics_group,
NULL,
};
void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
struct spi_transfer *xfer,
struct spi_controller *ctlr)
{
unsigned long flags;
int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
if (l2len < 0)
l2len = 0;
spin_lock_irqsave(&stats->lock, flags);
stats->transfers++;
stats->transfer_bytes_histo[l2len]++;
stats->bytes += xfer->len;
if ((xfer->tx_buf) &&
(xfer->tx_buf != ctlr->dummy_tx))
stats->bytes_tx += xfer->len;
if ((xfer->rx_buf) &&
(xfer->rx_buf != ctlr->dummy_rx))
stats->bytes_rx += xfer->len;
spin_unlock_irqrestore(&stats->lock, flags);
}
EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
* and the sysfs version makes coldplug work too.
*/
static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
const struct spi_device *sdev)
{
while (id->name[0]) {
if (!strcmp(sdev->modalias, id->name))
return id;
id++;
}
return NULL;
}
const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
{
const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
return spi_match_id(sdrv->id_table, sdev);
}
EXPORT_SYMBOL_GPL(spi_get_device_id);
static int spi_match_device(struct device *dev, struct device_driver *drv)
{
const struct spi_device *spi = to_spi_device(dev);
const struct spi_driver *sdrv = to_spi_driver(drv);
/* Check override first, and if set, only use the named driver */
if (spi->driver_override)
return strcmp(spi->driver_override, drv->name) == 0;
/* Attempt an OF style match */
if (of_driver_match_device(dev, drv))
return 1;
/* Then try ACPI */
if (acpi_driver_match_device(dev, drv))
return 1;
if (sdrv->id_table)
return !!spi_match_id(sdrv->id_table, spi);
return strcmp(spi->modalias, drv->name) == 0;
}
static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
{
const struct spi_device *spi = to_spi_device(dev);
int rc;
rc = acpi_device_uevent_modalias(dev, env);
if (rc != -ENODEV)
return rc;
return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
}
static int spi_probe(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
struct spi_device *spi = to_spi_device(dev);
int ret;
ret = of_clk_set_defaults(dev->of_node, false);
if (ret)
return ret;
if (dev->of_node) {
spi->irq = of_irq_get(dev->of_node, 0);
if (spi->irq == -EPROBE_DEFER)
return -EPROBE_DEFER;
if (spi->irq < 0)
spi->irq = 0;
}
ret = dev_pm_domain_attach(dev, true);
if (ret)
return ret;
if (sdrv->probe) {
ret = sdrv->probe(spi);
if (ret)
dev_pm_domain_detach(dev, true);
}
return ret;
}
static int spi_remove(struct device *dev)
{
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
if (sdrv->remove) {
int ret;
ret = sdrv->remove(to_spi_device(dev));
if (ret)
dev_warn(dev,
"Failed to unbind driver (%pe), ignoring\n",
ERR_PTR(ret));
}
dev_pm_domain_detach(dev, true);
return 0;
}
static void spi_shutdown(struct device *dev)
{
if (dev->driver) {
const struct spi_driver *sdrv = to_spi_driver(dev->driver);
if (sdrv->shutdown)
sdrv->shutdown(to_spi_device(dev));
}
}
struct bus_type spi_bus_type = {
.name = "spi",
.dev_groups = spi_dev_groups,
.match = spi_match_device,
.uevent = spi_uevent,
.probe = spi_probe,
.remove = spi_remove,
.shutdown = spi_shutdown,
};
EXPORT_SYMBOL_GPL(spi_bus_type);
/**
* __spi_register_driver - register a SPI driver
* @owner: owner module of the driver to register
* @sdrv: the driver to register
* Context: can sleep
*
* Return: zero on success, else a negative error code.
*/
int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
{
sdrv->driver.owner = owner;
sdrv->driver.bus = &spi_bus_type;
return driver_register(&sdrv->driver);
}
EXPORT_SYMBOL_GPL(__spi_register_driver);
/*-------------------------------------------------------------------------*/
/* SPI devices should normally not be created by SPI device drivers; that
* would make them board-specific. Similarly with SPI controller drivers.
* Device registration normally goes into like arch/.../mach.../board-YYY.c
* with other readonly (flashable) information about mainboard devices.
*/
struct boardinfo {
struct list_head list;
struct spi_board_info board_info;
};
static LIST_HEAD(board_list);
static LIST_HEAD(spi_controller_list);
/*
* Used to protect add/del operation for board_info list and
* spi_controller list, and their matching process
* also used to protect object of type struct idr
*/
static DEFINE_MUTEX(board_lock);
/*
* Prevents addition of devices with same chip select and
* addition of devices below an unregistering controller.
*/
static DEFINE_MUTEX(spi_add_lock);
/**
* spi_alloc_device - Allocate a new SPI device
* @ctlr: Controller to which device is connected
* Context: can sleep
*
* Allows a driver to allocate and initialize a spi_device without
* registering it immediately. This allows a driver to directly
* fill the spi_device with device parameters before calling
* spi_add_device() on it.
*
* Caller is responsible to call spi_add_device() on the returned
* spi_device structure to add it to the SPI controller. If the caller
* needs to discard the spi_device without adding it, then it should
* call spi_dev_put() on it.
*
* Return: a pointer to the new device, or NULL.
*/
struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
{
struct spi_device *spi;
if (!spi_controller_get(ctlr))
return NULL;
spi = kzalloc(sizeof(*spi), GFP_KERNEL);
if (!spi) {
spi_controller_put(ctlr);
return NULL;
}
spi->master = spi->controller = ctlr;
spi->dev.parent = &ctlr->dev;
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
spi->cs_gpio = -ENOENT;
spi->mode = ctlr->buswidth_override_bits;
spin_lock_init(&spi->statistics.lock);
device_initialize(&spi->dev);
return spi;
}
EXPORT_SYMBOL_GPL(spi_alloc_device);
static void spi_dev_set_name(struct spi_device *spi)
{
struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
if (adev) {
dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
return;
}
dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
spi->chip_select);
}
static int spi_dev_check(struct device *dev, void *data)
{
struct spi_device *spi = to_spi_device(dev);
struct spi_device *new_spi = data;
if (spi->controller == new_spi->controller &&
spi->chip_select == new_spi->chip_select)
return -EBUSY;
return 0;
}
static void spi_cleanup(struct spi_device *spi)
{
if (spi->controller->cleanup)
spi->controller->cleanup(spi);
}
/**
* spi_add_device - Add spi_device allocated with spi_alloc_device
* @spi: spi_device to register
*
* Companion function to spi_alloc_device. Devices allocated with
* spi_alloc_device can be added onto the spi bus with this function.
*
* Return: 0 on success; negative errno on failure
*/
int spi_add_device(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
struct device *dev = ctlr->dev.parent;
int status;
/* Chipselects are numbered 0..max; validate. */
if (spi->chip_select >= ctlr->num_chipselect) {
dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
ctlr->num_chipselect);
return -EINVAL;
}
/* Set the bus ID string */
spi_dev_set_name(spi);
/* We need to make sure there's no other device with this
* chipselect **BEFORE** we call setup(), else we'll trash
* its configuration. Lock against concurrent add() calls.
*/
mutex_lock(&spi_add_lock);
status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
if (status) {
dev_err(dev, "chipselect %d already in use\n",
spi->chip_select);
goto done;
}
/* Controller may unregister concurrently */
if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
!device_is_registered(&ctlr->dev)) {
status = -ENODEV;
goto done;
}
/* Descriptors take precedence */
if (ctlr->cs_gpiods)
spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
else if (ctlr->cs_gpios)
spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
/* Drivers may modify this initial i/o setup, but will
* normally rely on the device being setup. Devices
* using SPI_CS_HIGH can't coexist well otherwise...
*/
status = spi_setup(spi);
if (status < 0) {
dev_err(dev, "can't setup %s, status %d\n",
dev_name(&spi->dev), status);
goto done;
}
/* Device may be bound to an active driver when this returns */
status = device_add(&spi->dev);
if (status < 0) {
dev_err(dev, "can't add %s, status %d\n",
dev_name(&spi->dev), status);
spi_cleanup(spi);
} else {
dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
}
done:
mutex_unlock(&spi_add_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_add_device);
/**
* spi_new_device - instantiate one new SPI device
* @ctlr: Controller to which device is connected
* @chip: Describes the SPI device
* Context: can sleep
*
* On typical mainboards, this is purely internal; and it's not needed
* after board init creates the hard-wired devices. Some development
* platforms may not be able to use spi_register_board_info though, and
* this is exported so that for example a USB or parport based adapter
* driver could add devices (which it would learn about out-of-band).
*
* Return: the new device, or NULL.
*/
struct spi_device *spi_new_device(struct spi_controller *ctlr,
struct spi_board_info *chip)
{
struct spi_device *proxy;
int status;
/* NOTE: caller did any chip->bus_num checks necessary.
*
* Also, unless we change the return value convention to use
* error-or-pointer (not NULL-or-pointer), troubleshootability
* suggests syslogged diagnostics are best here (ugh).
*/
proxy = spi_alloc_device(ctlr);
if (!proxy)
return NULL;
WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
proxy->chip_select = chip->chip_select;
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
proxy->irq = chip->irq;
strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
if (chip->swnode) {
status = device_add_software_node(&proxy->dev, chip->swnode);
if (status) {
dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
chip->modalias, status);
goto err_dev_put;
}
}
status = spi_add_device(proxy);
if (status < 0)
goto err_dev_put;
return proxy;
err_dev_put:
device_remove_software_node(&proxy->dev);
spi_dev_put(proxy);
return NULL;
}
EXPORT_SYMBOL_GPL(spi_new_device);
/**
* spi_unregister_device - unregister a single SPI device
* @spi: spi_device to unregister
*
* Start making the passed SPI device vanish. Normally this would be handled
* by spi_unregister_controller().
*/
void spi_unregister_device(struct spi_device *spi)
{
if (!spi)
return;
if (spi->dev.of_node) {
of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
of_node_put(spi->dev.of_node);
}
if (ACPI_COMPANION(&spi->dev))
acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
device_remove_software_node(&spi->dev);
device_del(&spi->dev);
spi_cleanup(spi);
put_device(&spi->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_device);
static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
struct spi_board_info *bi)
{
struct spi_device *dev;
if (ctlr->bus_num != bi->bus_num)
return;
dev = spi_new_device(ctlr, bi);
if (!dev)
dev_err(ctlr->dev.parent, "can't create new device for %s\n",
bi->modalias);
}
/**
* spi_register_board_info - register SPI devices for a given board
* @info: array of chip descriptors
* @n: how many descriptors are provided
* Context: can sleep
*
* Board-specific early init code calls this (probably during arch_initcall)
* with segments of the SPI device table. Any device nodes are created later,
* after the relevant parent SPI controller (bus_num) is defined. We keep
* this table of devices forever, so that reloading a controller driver will
* not make Linux forget about these hard-wired devices.
*
* Other code can also call this, e.g. a particular add-on board might provide
* SPI devices through its expansion connector, so code initializing that board
* would naturally declare its SPI devices.
*
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*
* Return: zero on success, else a negative error code.
*/
int spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
struct boardinfo *bi;
int i;
if (!n)
return 0;
bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
if (!bi)
return -ENOMEM;
for (i = 0; i < n; i++, bi++, info++) {
struct spi_controller *ctlr;
memcpy(&bi->board_info, info, sizeof(*info));
mutex_lock(&board_lock);
list_add_tail(&bi->list, &board_list);
list_for_each_entry(ctlr, &spi_controller_list, list)
spi_match_controller_to_boardinfo(ctlr,
&bi->board_info);
mutex_unlock(&board_lock);
}
return 0;
}
/*-------------------------------------------------------------------------*/
static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
{
bool activate = enable;
/*
* Avoid calling into the driver (or doing delays) if the chip select
* isn't actually changing from the last time this was called.
*/
if (!force && (spi->controller->last_cs_enable == enable) &&
(spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
return;
spi->controller->last_cs_enable = enable;
spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
!spi->controller->set_cs_timing) {
if (activate)
spi_delay_exec(&spi->controller->cs_setup, NULL);
else
spi_delay_exec(&spi->controller->cs_hold, NULL);
}
if (spi->mode & SPI_CS_HIGH)
enable = !enable;
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
if (!(spi->mode & SPI_NO_CS)) {
if (spi->cs_gpiod) {
/*
* Historically ACPI has no means of the GPIO polarity and
* thus the SPISerialBus() resource defines it on the per-chip
* basis. In order to avoid a chain of negations, the GPIO
* polarity is considered being Active High. Even for the cases
* when _DSD() is involved (in the updated versions of ACPI)
* the GPIO CS polarity must be defined Active High to avoid
* ambiguity. That's why we use enable, that takes SPI_CS_HIGH
* into account.
*/
if (has_acpi_companion(&spi->dev))
gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
else
/* Polarity handled by GPIO library */
gpiod_set_value_cansleep(spi->cs_gpiod, activate);
} else {
/*
* invert the enable line, as active low is
* default for SPI.
*/
gpio_set_value_cansleep(spi->cs_gpio, !enable);
}
}
/* Some SPI masters need both GPIO CS & slave_select */
if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
spi->controller->set_cs)
spi->controller->set_cs(spi, !enable);
} else if (spi->controller->set_cs) {
spi->controller->set_cs(spi, !enable);
}
if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
!spi->controller->set_cs_timing) {
if (!activate)
spi_delay_exec(&spi->controller->cs_inactive, NULL);
}
}
#ifdef CONFIG_HAS_DMA
int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, void *buf, size_t len,
enum dma_data_direction dir)
{
const bool vmalloced_buf = is_vmalloc_addr(buf);
unsigned int max_seg_size = dma_get_max_seg_size(dev);
#ifdef CONFIG_HIGHMEM
const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
(unsigned long)buf < (PKMAP_BASE +
(LAST_PKMAP * PAGE_SIZE)));
#else
const bool kmap_buf = false;
#endif
int desc_len;
int sgs;
struct page *vm_page;
struct scatterlist *sg;
void *sg_buf;
size_t min;
int i, ret;
if (vmalloced_buf || kmap_buf) {
desc_len = min_t(int, max_seg_size, PAGE_SIZE);
sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
} else if (virt_addr_valid(buf)) {
desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
sgs = DIV_ROUND_UP(len, desc_len);
} else {
return -EINVAL;
}
ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
if (ret != 0)
return ret;
sg = &sgt->sgl[0];
for (i = 0; i < sgs; i++) {
if (vmalloced_buf || kmap_buf) {
/*
* Next scatterlist entry size is the minimum between
* the desc_len and the remaining buffer length that
* fits in a page.
*/
min = min_t(size_t, desc_len,
min_t(size_t, len,
PAGE_SIZE - offset_in_page(buf)));
if (vmalloced_buf)
vm_page = vmalloc_to_page(buf);
else
vm_page = kmap_to_page(buf);
if (!vm_page) {
sg_free_table(sgt);
return -ENOMEM;
}
sg_set_page(sg, vm_page,
min, offset_in_page(buf));
} else {
min = min_t(size_t, len, desc_len);
sg_buf = buf;
sg_set_buf(sg, sg_buf, min);
}
buf += min;
len -= min;
sg = sg_next(sg);
}
ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
if (!ret)
ret = -ENOMEM;
if (ret < 0) {
sg_free_table(sgt);
return ret;
}
sgt->nents = ret;
return 0;
}
void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
struct sg_table *sgt, enum dma_data_direction dir)
{
if (sgt->orig_nents) {
dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
sg_free_table(sgt);
}
}
static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct device *tx_dev, *rx_dev;
struct spi_transfer *xfer;
int ret;
if (!ctlr->can_dma)
return 0;
if (ctlr->dma_tx)
tx_dev = ctlr->dma_tx->device->dev;
else
tx_dev = ctlr->dev.parent;
if (ctlr->dma_rx)
rx_dev = ctlr->dma_rx->device->dev;
else
rx_dev = ctlr->dev.parent;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (!ctlr->can_dma(ctlr, msg->spi, xfer))
continue;
if (xfer->tx_buf != NULL) {
ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
(void *)xfer->tx_buf, xfer->len,
DMA_TO_DEVICE);
if (ret != 0)
return ret;
}
if (xfer->rx_buf != NULL) {
ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
xfer->rx_buf, xfer->len,
DMA_FROM_DEVICE);
if (ret != 0) {
spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
DMA_TO_DEVICE);
return ret;
}
}
}
ctlr->cur_msg_mapped = true;
return 0;
}
static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct spi_transfer *xfer;
struct device *tx_dev, *rx_dev;
if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
return 0;
if (ctlr->dma_tx)
tx_dev = ctlr->dma_tx->device->dev;
else
tx_dev = ctlr->dev.parent;
if (ctlr->dma_rx)
rx_dev = ctlr->dma_rx->device->dev;
else
rx_dev = ctlr->dev.parent;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (!ctlr->can_dma(ctlr, msg->spi, xfer))
continue;
spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
}
ctlr->cur_msg_mapped = false;
return 0;
}
#else /* !CONFIG_HAS_DMA */
static inline int __spi_map_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
return 0;
}
static inline int __spi_unmap_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
return 0;
}
#endif /* !CONFIG_HAS_DMA */
static inline int spi_unmap_msg(struct spi_controller *ctlr,
struct spi_message *msg)
{
struct spi_transfer *xfer;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
/*
* Restore the original value of tx_buf or rx_buf if they are
* NULL.
*/
if (xfer->tx_buf == ctlr->dummy_tx)
xfer->tx_buf = NULL;
if (xfer->rx_buf == ctlr->dummy_rx)
xfer->rx_buf = NULL;
}
return __spi_unmap_msg(ctlr, msg);
}
static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
{
struct spi_transfer *xfer;
void *tmp;
unsigned int max_tx, max_rx;
if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
&& !(msg->spi->mode & SPI_3WIRE)) {
max_tx = 0;
max_rx = 0;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
!xfer->tx_buf)
max_tx = max(xfer->len, max_tx);
if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
!xfer->rx_buf)
max_rx = max(xfer->len, max_rx);
}
if (max_tx) {
tmp = krealloc(ctlr->dummy_tx, max_tx,
GFP_KERNEL | GFP_DMA);
if (!tmp)
return -ENOMEM;
ctlr->dummy_tx = tmp;
memset(tmp, 0, max_tx);
}
if (max_rx) {
tmp = krealloc(ctlr->dummy_rx, max_rx,
GFP_KERNEL | GFP_DMA);
if (!tmp)
return -ENOMEM;
ctlr->dummy_rx = tmp;
}
if (max_tx || max_rx) {
list_for_each_entry(xfer, &msg->transfers,
transfer_list) {
if (!xfer->len)
continue;
if (!xfer->tx_buf)
xfer->tx_buf = ctlr->dummy_tx;
if (!xfer->rx_buf)
xfer->rx_buf = ctlr->dummy_rx;
}
}
}
return __spi_map_msg(ctlr, msg);
}
static int spi_transfer_wait(struct spi_controller *ctlr,
struct spi_message *msg,
struct spi_transfer *xfer)
{
struct spi_statistics *statm = &ctlr->statistics;
struct spi_statistics *stats = &msg->spi->statistics;
u32 speed_hz = xfer->speed_hz;
unsigned long long ms;
if (spi_controller_is_slave(ctlr)) {
if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
return -EINTR;
}
} else {
if (!speed_hz)
speed_hz = 100000;
ms = 8LL * 1000LL * xfer->len;
do_div(ms, speed_hz);
ms += ms + 200; /* some tolerance */
if (ms > UINT_MAX)
ms = UINT_MAX;
ms = wait_for_completion_timeout(&ctlr->xfer_completion,
msecs_to_jiffies(ms));
if (ms == 0) {
SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
dev_err(&msg->spi->dev,
"SPI transfer timed out\n");
return -ETIMEDOUT;
}
}
return 0;
}
static void _spi_transfer_delay_ns(u32 ns)
{
if (!ns)
return;
if (ns <= 1000) {
ndelay(ns);
} else {
u32 us = DIV_ROUND_UP(ns, 1000);
if (us <= 10)
udelay(us);
else
usleep_range(us, us + DIV_ROUND_UP(us, 10));
}
}
int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
{
u32 delay = _delay->value;
u32 unit = _delay->unit;
u32 hz;
if (!delay)
return 0;
switch (unit) {
case SPI_DELAY_UNIT_USECS:
delay *= 1000;
break;
case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
break;
case SPI_DELAY_UNIT_SCK:
/* clock cycles need to be obtained from spi_transfer */
if (!xfer)
return -EINVAL;
/* if there is no effective speed know, then approximate
* by underestimating with half the requested hz
*/
hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
if (!hz)
return -EINVAL;
delay *= DIV_ROUND_UP(1000000000, hz);
break;
default:
return -EINVAL;
}
return delay;
}
EXPORT_SYMBOL_GPL(spi_delay_to_ns);
int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
{
int delay;
might_sleep();
if (!_delay)
return -EINVAL;
delay = spi_delay_to_ns(_delay, xfer);
if (delay < 0)
return delay;
_spi_transfer_delay_ns(delay);
return 0;
}
EXPORT_SYMBOL_GPL(spi_delay_exec);
static void _spi_transfer_cs_change_delay(struct spi_message *msg,
struct spi_transfer *xfer)
{
u32 delay = xfer->cs_change_delay.value;
u32 unit = xfer->cs_change_delay.unit;
int ret;
/* return early on "fast" mode - for everything but USECS */
if (!delay) {
if (unit == SPI_DELAY_UNIT_USECS)
_spi_transfer_delay_ns(10000);
return;
}
ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
if (ret) {
dev_err_once(&msg->spi->dev,
"Use of unsupported delay unit %i, using default of 10us\n",
unit);
_spi_transfer_delay_ns(10000);
}
}
/*
* spi_transfer_one_message - Default implementation of transfer_one_message()
*
* This is a standard implementation of transfer_one_message() for
* drivers which implement a transfer_one() operation. It provides
* standard handling of delays and chip select management.
*/
static int spi_transfer_one_message(struct spi_controller *ctlr,
struct spi_message *msg)
{
struct spi_transfer *xfer;
bool keep_cs = false;
int ret = 0;
struct spi_statistics *statm = &ctlr->statistics;
struct spi_statistics *stats = &msg->spi->statistics;
spi_set_cs(msg->spi, true, false);
SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
trace_spi_transfer_start(msg, xfer);
spi_statistics_add_transfer_stats(statm, xfer, ctlr);
spi_statistics_add_transfer_stats(stats, xfer, ctlr);
if (!ctlr->ptp_sts_supported) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
reinit_completion(&ctlr->xfer_completion);
fallback_pio:
ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
if (ret < 0) {
if (ctlr->cur_msg_mapped &&
(xfer->error & SPI_TRANS_FAIL_NO_START)) {
__spi_unmap_msg(ctlr, msg);
ctlr->fallback = true;
xfer->error &= ~SPI_TRANS_FAIL_NO_START;
goto fallback_pio;
}
SPI_STATISTICS_INCREMENT_FIELD(statm,
errors);
SPI_STATISTICS_INCREMENT_FIELD(stats,
errors);
dev_err(&msg->spi->dev,
"SPI transfer failed: %d\n", ret);
goto out;
}
if (ret > 0) {
ret = spi_transfer_wait(ctlr, msg, xfer);
if (ret < 0)
msg->status = ret;
}
} else {
if (xfer->len)
dev_err(&msg->spi->dev,
"Bufferless transfer has length %u\n",
xfer->len);
}
if (!ctlr->ptp_sts_supported) {
ptp_read_system_postts(xfer->ptp_sts);
xfer->ptp_sts_word_post = xfer->len;
}
trace_spi_transfer_stop(msg, xfer);
if (msg->status != -EINPROGRESS)
goto out;
spi_transfer_delay_exec(xfer);
if (xfer->cs_change) {
if (list_is_last(&xfer->transfer_list,
&msg->transfers)) {
keep_cs = true;
} else {
spi_set_cs(msg->spi, false, false);
_spi_transfer_cs_change_delay(msg, xfer);
spi_set_cs(msg->spi, true, false);
}
}
msg->actual_length += xfer->len;
}
out:
if (ret != 0 || !keep_cs)
spi_set_cs(msg->spi, false, false);
if (msg->status == -EINPROGRESS)
msg->status = ret;
if (msg->status && ctlr->handle_err)
ctlr->handle_err(ctlr, msg);
spi_finalize_current_message(ctlr);
return ret;
}
/**
* spi_finalize_current_transfer - report completion of a transfer
* @ctlr: the controller reporting completion
*
* Called by SPI drivers using the core transfer_one_message()
* implementation to notify it that the current interrupt driven
* transfer has finished and the next one may be scheduled.
*/
void spi_finalize_current_transfer(struct spi_controller *ctlr)
{
complete(&ctlr->xfer_completion);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
static void spi_idle_runtime_pm(struct spi_controller *ctlr)
{
if (ctlr->auto_runtime_pm) {
pm_runtime_mark_last_busy(ctlr->dev.parent);
pm_runtime_put_autosuspend(ctlr->dev.parent);
}
}
/**
* __spi_pump_messages - function which processes spi message queue
* @ctlr: controller to process queue for
* @in_kthread: true if we are in the context of the message pump thread
*
* This function checks if there is any spi message in the queue that
* needs processing and if so call out to the driver to initialize hardware
* and transfer each message.
*
* Note that it is called both from the kthread itself and also from
* inside spi_sync(); the queue extraction handling at the top of the
* function should deal with this safely.
*/
static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
{
struct spi_transfer *xfer;
struct spi_message *msg;
bool was_busy = false;
unsigned long flags;
int ret;
/* Lock queue */
spin_lock_irqsave(&ctlr->queue_lock, flags);
/* Make sure we are not already running a message */
if (ctlr->cur_msg) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
/* If another context is idling the device then defer */
if (ctlr->idling) {
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
/* Check if the queue is idle */
if (list_empty(&ctlr->queue) || !ctlr->running) {
if (!ctlr->busy) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
/* Defer any non-atomic teardown to the thread */
if (!in_kthread) {
if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
!ctlr->unprepare_transfer_hardware) {
spi_idle_runtime_pm(ctlr);
ctlr->busy = false;
trace_spi_controller_idle(ctlr);
} else {
kthread_queue_work(ctlr->kworker,
&ctlr->pump_messages);
}
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
ctlr->busy = false;
ctlr->idling = true;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
kfree(ctlr->dummy_rx);
ctlr->dummy_rx = NULL;
kfree(ctlr->dummy_tx);
ctlr->dummy_tx = NULL;
if (ctlr->unprepare_transfer_hardware &&
ctlr->unprepare_transfer_hardware(ctlr))
dev_err(&ctlr->dev,
"failed to unprepare transfer hardware\n");
spi_idle_runtime_pm(ctlr);
trace_spi_controller_idle(ctlr);
spin_lock_irqsave(&ctlr->queue_lock, flags);
ctlr->idling = false;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return;
}
/* Extract head of queue */
msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
ctlr->cur_msg = msg;
list_del_init(&msg->queue);
if (ctlr->busy)
was_busy = true;
else
ctlr->busy = true;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
mutex_lock(&ctlr->io_mutex);
if (!was_busy && ctlr->auto_runtime_pm) {
ret = pm_runtime_get_sync(ctlr->dev.parent);
if (ret < 0) {
pm_runtime_put_noidle(ctlr->dev.parent);
dev_err(&ctlr->dev, "Failed to power device: %d\n",
ret);
mutex_unlock(&ctlr->io_mutex);
return;
}
}
if (!was_busy)
trace_spi_controller_busy(ctlr);
if (!was_busy && ctlr->prepare_transfer_hardware) {
ret = ctlr->prepare_transfer_hardware(ctlr);
if (ret) {
dev_err(&ctlr->dev,
"failed to prepare transfer hardware: %d\n",
ret);
if (ctlr->auto_runtime_pm)
pm_runtime_put(ctlr->dev.parent);
msg->status = ret;
spi_finalize_current_message(ctlr);
mutex_unlock(&ctlr->io_mutex);
return;
}
}
trace_spi_message_start(msg);
if (ctlr->prepare_message) {
ret = ctlr->prepare_message(ctlr, msg);
if (ret) {
dev_err(&ctlr->dev, "failed to prepare message: %d\n",
ret);
msg->status = ret;
spi_finalize_current_message(ctlr);
goto out;
}
ctlr->cur_msg_prepared = true;
}
ret = spi_map_msg(ctlr, msg);
if (ret) {
msg->status = ret;
spi_finalize_current_message(ctlr);
goto out;
}
if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
}
ret = ctlr->transfer_one_message(ctlr, msg);
if (ret) {
dev_err(&ctlr->dev,
"failed to transfer one message from queue\n");
goto out;
}
out:
mutex_unlock(&ctlr->io_mutex);
/* Prod the scheduler in case transfer_one() was busy waiting */
if (!ret)
cond_resched();
}
/**
* spi_pump_messages - kthread work function which processes spi message queue
* @work: pointer to kthread work struct contained in the controller struct
*/
static void spi_pump_messages(struct kthread_work *work)
{
struct spi_controller *ctlr =
container_of(work, struct spi_controller, pump_messages);
__spi_pump_messages(ctlr, true);
}
/**
* spi_take_timestamp_pre - helper for drivers to collect the beginning of the
* TX timestamp for the requested byte from the SPI
* transfer. The frequency with which this function
* must be called (once per word, once for the whole
* transfer, once per batch of words etc) is arbitrary
* as long as the @tx buffer offset is greater than or
* equal to the requested byte at the time of the
* call. The timestamp is only taken once, at the
* first such call. It is assumed that the driver
* advances its @tx buffer pointer monotonically.
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
* @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will disable IRQs and preemption for the duration of the
* transfer, for less jitter in time measurement. Only compatible
* with PIO drivers. If true, must follow up with
* spi_take_timestamp_post or otherwise system will crash.
* WARNING: for fully predictable results, the CPU frequency must
* also be under control (governor).
*/
void spi_take_timestamp_pre(struct spi_controller *ctlr,
struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{
if (!xfer->ptp_sts)
return;
if (xfer->timestamped)
return;
if (progress > xfer->ptp_sts_word_pre)
return;
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_pre = progress;
if (irqs_off) {
local_irq_save(ctlr->irq_flags);
preempt_disable();
}
ptp_read_system_prets(xfer->ptp_sts);
}
EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
/**
* spi_take_timestamp_post - helper for drivers to collect the end of the
* TX timestamp for the requested byte from the SPI
* transfer. Can be called with an arbitrary
* frequency: only the first call where @tx exceeds
* or is equal to the requested word will be
* timestamped.
* @ctlr: Pointer to the spi_controller structure of the driver
* @xfer: Pointer to the transfer being timestamped
* @progress: How many words (not bytes) have been transferred so far
* @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
*/
void spi_take_timestamp_post(struct spi_controller *ctlr,
struct spi_transfer *xfer,
size_t progress, bool irqs_off)
{
if (!xfer->ptp_sts)
return;
if (xfer->timestamped)
return;
if (progress < xfer->ptp_sts_word_post)
return;
ptp_read_system_postts(xfer->ptp_sts);
if (irqs_off) {
local_irq_restore(ctlr->irq_flags);
preempt_enable();
}
/* Capture the resolution of the timestamp */
xfer->ptp_sts_word_post = progress;
xfer->timestamped = true;
}
EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
/**
* spi_set_thread_rt - set the controller to pump at realtime priority
* @ctlr: controller to boost priority of
*
* This can be called because the controller requested realtime priority
* (by setting the ->rt value before calling spi_register_controller()) or
* because a device on the bus said that its transfers needed realtime
* priority.
*
* NOTE: at the moment if any device on a bus says it needs realtime then
* the thread will be at realtime priority for all transfers on that
* controller. If this eventually becomes a problem we may see if we can
* find a way to boost the priority only temporarily during relevant
* transfers.
*/
static void spi_set_thread_rt(struct spi_controller *ctlr)
{
dev_info(&ctlr->dev,
"will run message pump with realtime priority\n");
sched_set_fifo(ctlr->kworker->task);
}
static int spi_init_queue(struct spi_controller *ctlr)
{
ctlr->running = false;
ctlr->busy = false;
ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
if (IS_ERR(ctlr->kworker)) {
dev_err(&ctlr->dev, "failed to create message pump kworker\n");
return PTR_ERR(ctlr->kworker);
}
kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
/*
* Controller config will indicate if this controller should run the
* message pump with high (realtime) priority to reduce the transfer
* latency on the bus by minimising the delay between a transfer
* request and the scheduling of the message pump thread. Without this
* setting the message pump thread will remain at default priority.
*/
if (ctlr->rt)
spi_set_thread_rt(ctlr);
return 0;
}
/**
* spi_get_next_queued_message() - called by driver to check for queued
* messages
* @ctlr: the controller to check for queued messages
*
* If there are more messages in the queue, the next message is returned from
* this call.
*
* Return: the next message in the queue, else NULL if the queue is empty.
*/
struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
{
struct spi_message *next;
unsigned long flags;
/* get a pointer to the next message, if any */
spin_lock_irqsave(&ctlr->queue_lock, flags);
next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
queue);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return next;
}
EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
/**
* spi_finalize_current_message() - the current message is complete
* @ctlr: the controller to return the message to
*
* Called by the driver to notify the core that the message in the front of the
* queue is complete and can be removed from the queue.
*/
void spi_finalize_current_message(struct spi_controller *ctlr)
{
struct spi_transfer *xfer;
struct spi_message *mesg;
unsigned long flags;
int ret;
spin_lock_irqsave(&ctlr->queue_lock, flags);
mesg = ctlr->cur_msg;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
ptp_read_system_postts(xfer->ptp_sts);
xfer->ptp_sts_word_post = xfer->len;
}
}
if (unlikely(ctlr->ptp_sts_supported))
list_for_each_entry(xfer, &mesg->transfers, transfer_list)
WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
spi_unmap_msg(ctlr, mesg);
/* In the prepare_messages callback the spi bus has the opportunity to
* split a transfer to smaller chunks.
* Release splited transfers here since spi_map_msg is done on the
* splited transfers.
*/
spi_res_release(ctlr, mesg);
if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
ret = ctlr->unprepare_message(ctlr, mesg);
if (ret) {
dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
ret);
}
}
spin_lock_irqsave(&ctlr->queue_lock, flags);
ctlr->cur_msg = NULL;
ctlr->cur_msg_prepared = false;
ctlr->fallback = false;
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
trace_spi_message_done(mesg);
mesg->state = NULL;
if (mesg->complete)
mesg->complete(mesg->context);
}
EXPORT_SYMBOL_GPL(spi_finalize_current_message);
static int spi_start_queue(struct spi_controller *ctlr)
{
unsigned long flags;
spin_lock_irqsave(&ctlr->queue_lock, flags);
if (ctlr->running || ctlr->busy) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return -EBUSY;
}
ctlr->running = true;
ctlr->cur_msg = NULL;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
return 0;
}
static int spi_stop_queue(struct spi_controller *ctlr)
{
unsigned long flags;
unsigned limit = 500;
int ret = 0;
spin_lock_irqsave(&ctlr->queue_lock, flags);
/*
* This is a bit lame, but is optimized for the common execution path.
* A wait_queue on the ctlr->busy could be used, but then the common
* execution path (pump_messages) would be required to call wake_up or
* friends on every SPI message. Do this instead.
*/
while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
usleep_range(10000, 11000);
spin_lock_irqsave(&ctlr->queue_lock, flags);
}
if (!list_empty(&ctlr->queue) || ctlr->busy)
ret = -EBUSY;
else
ctlr->running = false;
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
if (ret) {
dev_warn(&ctlr->dev, "could not stop message queue\n");
return ret;
}
return ret;
}
static int spi_destroy_queue(struct spi_controller *ctlr)
{
int ret;
ret = spi_stop_queue(ctlr);
/*
* kthread_flush_worker will block until all work is done.
* If the reason that stop_queue timed out is that the work will never
* finish, then it does no good to call flush/stop thread, so
* return anyway.
*/
if (ret) {
dev_err(&ctlr->dev, "problem destroying queue\n");
return ret;
}
kthread_destroy_worker(ctlr->kworker);
return 0;
}
static int __spi_queued_transfer(struct spi_device *spi,
struct spi_message *msg,
bool need_pump)
{
struct spi_controller *ctlr = spi->controller;
unsigned long flags;
spin_lock_irqsave(&ctlr->queue_lock, flags);
if (!ctlr->running) {
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return -ESHUTDOWN;
}
msg->actual_length = 0;
msg->status = -EINPROGRESS;
list_add_tail(&msg->queue, &ctlr->queue);
if (!ctlr->busy && need_pump)
kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
spin_unlock_irqrestore(&ctlr->queue_lock, flags);
return 0;
}
/**
* spi_queued_transfer - transfer function for queued transfers
* @spi: spi device which is requesting transfer
* @msg: spi message which is to handled is queued to driver queue
*
* Return: zero on success, else a negative error code.
*/
static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
{
return __spi_queued_transfer(spi, msg, true);
}
static int spi_controller_initialize_queue(struct spi_controller *ctlr)
{
int ret;
ctlr->transfer = spi_queued_transfer;
if (!ctlr->transfer_one_message)
ctlr->transfer_one_message = spi_transfer_one_message;
/* Initialize and start queue */
ret = spi_init_queue(ctlr);
if (ret) {
dev_err(&ctlr->dev, "problem initializing queue\n");
goto err_init_queue;
}
ctlr->queued = true;
ret = spi_start_queue(ctlr);
if (ret) {
dev_err(&ctlr->dev, "problem starting queue\n");
goto err_start_queue;
}
return 0;
err_start_queue:
spi_destroy_queue(ctlr);
err_init_queue:
return ret;
}
/**
* spi_flush_queue - Send all pending messages in the queue from the callers'
* context
* @ctlr: controller to process queue for
*
* This should be used when one wants to ensure all pending messages have been
* sent before doing something. Is used by the spi-mem code to make sure SPI
* memory operations do not preempt regular SPI transfers that have been queued
* before the spi-mem operation.
*/
void spi_flush_queue(struct spi_controller *ctlr)
{
if (ctlr->transfer == spi_queued_transfer)
__spi_pump_messages(ctlr, false);
}
/*-------------------------------------------------------------------------*/
#if defined(CONFIG_OF)
static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
struct device_node *nc)
{
u32 value;
int rc;
/* Mode (clock phase/polarity/etc.) */
if (of_property_read_bool(nc, "spi-cpha"))
spi->mode |= SPI_CPHA;
if (of_property_read_bool(nc, "spi-cpol"))
spi->mode |= SPI_CPOL;
if (of_property_read_bool(nc, "spi-3wire"))
spi->mode |= SPI_3WIRE;
if (of_property_read_bool(nc, "spi-lsb-first"))
spi->mode |= SPI_LSB_FIRST;
if (of_property_read_bool(nc, "spi-cs-high"))
spi->mode |= SPI_CS_HIGH;
/* Device DUAL/QUAD mode */
if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
switch (value) {
case 0:
spi->mode |= SPI_NO_TX;
break;
case 1:
break;
case 2:
spi->mode |= SPI_TX_DUAL;
break;
case 4:
spi->mode |= SPI_TX_QUAD;
break;
case 8:
spi->mode |= SPI_TX_OCTAL;
break;
default:
dev_warn(&ctlr->dev,
"spi-tx-bus-width %d not supported\n",
value);
break;
}
}
if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
switch (value) {
case 0:
spi->mode |= SPI_NO_RX;
break;
case 1:
break;
case 2:
spi->mode |= SPI_RX_DUAL;
break;
case 4:
spi->mode |= SPI_RX_QUAD;
break;
case 8:
spi->mode |= SPI_RX_OCTAL;
break;
default:
dev_warn(&ctlr->dev,
"spi-rx-bus-width %d not supported\n",
value);
break;
}
}
if (spi_controller_is_slave(ctlr)) {
if (!of_node_name_eq(nc, "slave")) {
dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
nc);
return -EINVAL;
}
return 0;
}
/* Device address */
rc = of_property_read_u32(nc, "reg", &value);
if (rc) {
dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
nc, rc);
return rc;
}
spi->chip_select = value;
/* Device speed */
if (!of_property_read_u32(nc, "spi-max-frequency", &value))
spi->max_speed_hz = value;
return 0;
}
static struct spi_device *
of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
{
struct spi_device *spi;
int rc;
/* Alloc an spi_device */
spi = spi_alloc_device(ctlr);
if (!spi) {
dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
rc = -ENOMEM;
goto err_out;
}
/* Select device driver */
rc = of_modalias_node(nc, spi->modalias,
sizeof(spi->modalias));
if (rc < 0) {
dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
goto err_out;
}
rc = of_spi_parse_dt(ctlr, spi, nc);
if (rc)
goto err_out;
/* Store a pointer to the node in the device structure */
of_node_get(nc);
spi->dev.of_node = nc;
/* Register the new device */
rc = spi_add_device(spi);
if (rc) {
dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
goto err_of_node_put;
}
return spi;
err_of_node_put:
of_node_put(nc);
err_out:
spi_dev_put(spi);
return ERR_PTR(rc);
}
/**
* of_register_spi_devices() - Register child devices onto the SPI bus
* @ctlr: Pointer to spi_controller device
*
* Registers an spi_device for each child node of controller node which
* represents a valid SPI slave.
*/
static void of_register_spi_devices(struct spi_controller *ctlr)
{
struct spi_device *spi;
struct device_node *nc;
if (!ctlr->dev.of_node)
return;
for_each_available_child_of_node(ctlr->dev.of_node, nc) {
if (of_node_test_and_set_flag(nc, OF_POPULATED))
continue;
spi = of_register_spi_device(ctlr, nc);
if (IS_ERR(spi)) {
dev_warn(&ctlr->dev,
"Failed to create SPI device for %pOF\n", nc);
of_node_clear_flag(nc, OF_POPULATED);
}
}
}
#else
static void of_register_spi_devices(struct spi_controller *ctlr) { }
#endif
#ifdef CONFIG_ACPI
struct acpi_spi_lookup {
struct spi_controller *ctlr;
u32 max_speed_hz;
u32 mode;
int irq;
u8 bits_per_word;
u8 chip_select;
};
static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
struct acpi_spi_lookup *lookup)
{
const union acpi_object *obj;
if (!x86_apple_machine)
return;
if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length >= 4)
lookup->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8)
lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_LSB_FIRST;
if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_CPOL;
if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
&& obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer)
lookup->mode |= SPI_CPHA;
}
static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
{
struct acpi_spi_lookup *lookup = data;
struct spi_controller *ctlr = lookup->ctlr;
if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
struct acpi_resource_spi_serialbus *sb;
acpi_handle parent_handle;
acpi_status status;
sb = &ares->data.spi_serial_bus;
if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
status = acpi_get_handle(NULL,
sb->resource_source.string_ptr,
&parent_handle);
if (ACPI_FAILURE(status) ||
ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
return -ENODEV;
/*
* ACPI DeviceSelection numbering is handled by the
* host controller driver in Windows and can vary
* from driver to driver. In Linux we always expect
* 0 .. max - 1 so we need to ask the driver to
* translate between the two schemes.
*/
if (ctlr->fw_translate_cs) {
int cs = ctlr->fw_translate_cs(ctlr,
sb->device_selection);
if (cs < 0)
return cs;
lookup->chip_select = cs;
} else {
lookup->chip_select = sb->device_selection;
}
lookup->max_speed_hz = sb->connection_speed;
lookup->bits_per_word = sb->data_bit_length;
if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
lookup->mode |= SPI_CPHA;
if (sb->clock_polarity == ACPI_SPI_START_HIGH)
lookup->mode |= SPI_CPOL;
if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
lookup->mode |= SPI_CS_HIGH;
}
} else if (lookup->irq < 0) {
struct resource r;
if (acpi_dev_resource_interrupt(ares, 0, &r))
lookup->irq = r.start;
}
/* Always tell the ACPI core to skip this resource */
return 1;
}
static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
struct acpi_device *adev)
{
acpi_handle parent_handle = NULL;
struct list_head resource_list;
struct acpi_spi_lookup lookup = {};
struct spi_device *spi;
int ret;
if (acpi_bus_get_status(adev) || !adev->status.present ||
acpi_device_enumerated(adev))
return AE_OK;
lookup.ctlr = ctlr;
lookup.irq = -1;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
acpi_spi_add_resource, &lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0)
/* found SPI in _CRS but it points to another controller */
return AE_OK;
if (!lookup.max_speed_hz &&
ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
/* Apple does not use _CRS but nested devices for SPI slaves */
acpi_spi_parse_apple_properties(adev, &lookup);
}
if (!lookup.max_speed_hz)
return AE_OK;
spi = spi_alloc_device(ctlr);
if (!spi) {
dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
dev_name(&adev->dev));
return AE_NO_MEMORY;
}
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
spi->mode |= lookup.mode;
spi->irq = lookup.irq;
spi->bits_per_word = lookup.bits_per_word;
spi->chip_select = lookup.chip_select;
acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
sizeof(spi->modalias));
if (spi->irq < 0)
spi->irq = acpi_dev_gpio_irq_get(adev, 0);
acpi_device_set_enumerated(adev);
adev->power.flags.ignore_parent = true;
if (spi_add_device(spi)) {
adev->power.flags.ignore_parent = false;
dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
dev_name(&adev->dev));
spi_dev_put(spi);
}
return AE_OK;
}
static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct spi_controller *ctlr = data;
struct acpi_device *adev;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
return acpi_register_spi_device(ctlr, adev);
}
#define SPI_ACPI_ENUMERATE_MAX_DEPTH 32
static void acpi_register_spi_devices(struct spi_controller *ctlr)
{
acpi_status status;
acpi_handle handle;
handle = ACPI_HANDLE(ctlr->dev.parent);
if (!handle)
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
SPI_ACPI_ENUMERATE_MAX_DEPTH,
acpi_spi_add_device, NULL, ctlr, NULL);
if (ACPI_FAILURE(status))
dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
}
#else
static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
#endif /* CONFIG_ACPI */
static void spi_controller_release(struct device *dev)
{
struct spi_controller *ctlr;
ctlr = container_of(dev, struct spi_controller, dev);
kfree(ctlr);
}
static struct class spi_master_class = {
.name = "spi_master",
.owner = THIS_MODULE,
.dev_release = spi_controller_release,
.dev_groups = spi_master_groups,
};
#ifdef CONFIG_SPI_SLAVE
/**
* spi_slave_abort - abort the ongoing transfer request on an SPI slave
* controller
* @spi: device used for the current transfer
*/
int spi_slave_abort(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
return ctlr->slave_abort(ctlr);
return -ENOTSUPP;
}
EXPORT_SYMBOL_GPL(spi_slave_abort);
static int match_true(struct device *dev, void *data)
{
return 1;
}
static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct spi_controller *ctlr = container_of(dev, struct spi_controller,
dev);
struct device *child;
child = device_find_child(&ctlr->dev, NULL, match_true);
return sprintf(buf, "%s\n",
child ? to_spi_device(child)->modalias : NULL);
}
static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct spi_controller *ctlr = container_of(dev, struct spi_controller,
dev);
struct spi_device *spi;
struct device *child;
char name[32];
int rc;
rc = sscanf(buf, "%31s", name);
if (rc != 1 || !name[0])
return -EINVAL;
child = device_find_child(&ctlr->dev, NULL, match_true);
if (child) {
/* Remove registered slave */
device_unregister(child);
put_device(child);
}
if (strcmp(name, "(null)")) {
/* Register new slave */
spi = spi_alloc_device(ctlr);
if (!spi)
return -ENOMEM;
strlcpy(spi->modalias, name, sizeof(spi->modalias));
rc = spi_add_device(spi);
if (rc) {
spi_dev_put(spi);
return rc;
}
}
return count;
}
static DEVICE_ATTR_RW(slave);
static struct attribute *spi_slave_attrs[] = {
&dev_attr_slave.attr,
NULL,
};
static const struct attribute_group spi_slave_group = {
.attrs = spi_slave_attrs,
};
static const struct attribute_group *spi_slave_groups[] = {
&spi_controller_statistics_group,
&spi_slave_group,
NULL,
};
static struct class spi_slave_class = {
.name = "spi_slave",
.owner = THIS_MODULE,
.dev_release = spi_controller_release,
.dev_groups = spi_slave_groups,
};
#else
extern struct class spi_slave_class; /* dummy */
#endif
/**
* __spi_alloc_controller - allocate an SPI master or slave controller
* @dev: the controller, possibly using the platform_bus
* @size: how much zeroed driver-private data to allocate; the pointer to this
* memory is in the driver_data field of the returned device, accessible
* with spi_controller_get_devdata(); the memory is cacheline aligned;
* drivers granting DMA access to portions of their private data need to
* round up @size using ALIGN(size, dma_get_cache_alignment()).
* @slave: flag indicating whether to allocate an SPI master (false) or SPI
* slave (true) controller
* Context: can sleep
*
* This call is used only by SPI controller drivers, which are the
* only ones directly touching chip registers. It's how they allocate
* an spi_controller structure, prior to calling spi_register_controller().
*
* This must be called from context that can sleep.
*
* The caller is responsible for assigning the bus number and initializing the
* controller's methods before calling spi_register_controller(); and (after
* errors adding the device) calling spi_controller_put() to prevent a memory
* leak.
*
* Return: the SPI controller structure on success, else NULL.
*/
struct spi_controller *__spi_alloc_controller(struct device *dev,
unsigned int size, bool slave)
{
struct spi_controller *ctlr;
size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
if (!dev)
return NULL;
ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
if (!ctlr)
return NULL;
device_initialize(&ctlr->dev);
ctlr->bus_num = -1;
ctlr->num_chipselect = 1;
ctlr->slave = slave;
if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
ctlr->dev.class = &spi_slave_class;
else
ctlr->dev.class = &spi_master_class;
ctlr->dev.parent = dev;
pm_suspend_ignore_children(&ctlr->dev, true);
spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
return ctlr;
}
EXPORT_SYMBOL_GPL(__spi_alloc_controller);
static void devm_spi_release_controller(struct device *dev, void *ctlr)
{
spi_controller_put(*(struct spi_controller **)ctlr);
}
/**
* __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
* @dev: physical device of SPI controller
* @size: how much zeroed driver-private data to allocate
* @slave: whether to allocate an SPI master (false) or SPI slave (true)
* Context: can sleep
*
* Allocate an SPI controller and automatically release a reference on it
* when @dev is unbound from its driver. Drivers are thus relieved from
* having to call spi_controller_put().
*
* The arguments to this function are identical to __spi_alloc_controller().
*
* Return: the SPI controller structure on success, else NULL.
*/
struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
unsigned int size,
bool slave)
{
struct spi_controller **ptr, *ctlr;
ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return NULL;
ctlr = __spi_alloc_controller(dev, size, slave);
if (ctlr) {
ctlr->devm_allocated = true;
*ptr = ctlr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return ctlr;
}
EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
#ifdef CONFIG_OF
static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
{
int nb, i, *cs;
struct device_node *np = ctlr->dev.of_node;
if (!np)
return 0;
nb = of_gpio_named_count(np, "cs-gpios");
ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
/* Return error only for an incorrectly formed cs-gpios property */
if (nb == 0 || nb == -ENOENT)
return 0;
else if (nb < 0)
return nb;
cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
GFP_KERNEL);
ctlr->cs_gpios = cs;
if (!ctlr->cs_gpios)
return -ENOMEM;
for (i = 0; i < ctlr->num_chipselect; i++)
cs[i] = -ENOENT;
for (i = 0; i < nb; i++)
cs[i] = of_get_named_gpio(np, "cs-gpios", i);
return 0;
}
#else
static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
{
return 0;
}
#endif
/**
* spi_get_gpio_descs() - grab chip select GPIOs for the master
* @ctlr: The SPI master to grab GPIO descriptors for
*/
static int spi_get_gpio_descs(struct spi_controller *ctlr)
{
int nb, i;
struct gpio_desc **cs;
struct device *dev = &ctlr->dev;
unsigned long native_cs_mask = 0;
unsigned int num_cs_gpios = 0;
nb = gpiod_count(dev, "cs");
if (nb < 0) {
/* No GPIOs at all is fine, else return the error */
if (nb == -ENOENT)
return 0;
return nb;
}
ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
GFP_KERNEL);
if (!cs)
return -ENOMEM;
ctlr->cs_gpiods = cs;
for (i = 0; i < nb; i++) {
/*
* Most chipselects are active low, the inverted
* semantics are handled by special quirks in gpiolib,
* so initializing them GPIOD_OUT_LOW here means
* "unasserted", in most cases this will drive the physical
* line high.
*/
cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
GPIOD_OUT_LOW);
if (IS_ERR(cs[i]))
return PTR_ERR(cs[i]);
if (cs[i]) {
/*
* If we find a CS GPIO, name it after the device and
* chip select line.
*/
char *gpioname;
gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
dev_name(dev), i);
if (!gpioname)
return -ENOMEM;
gpiod_set_consumer_name(cs[i], gpioname);
num_cs_gpios++;
continue;
}
if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
dev_err(dev, "Invalid native chip select %d\n", i);
return -EINVAL;
}
native_cs_mask |= BIT(i);
}
ctlr->unused_native_cs = ffz(native_cs_mask);
if (num_cs_gpios && ctlr->max_native_cs &&
ctlr->unused_native_cs >= ctlr->max_native_cs) {
dev_err(dev, "No unused native chip select available\n");
return -EINVAL;
}
return 0;
}
static int spi_controller_check_ops(struct spi_controller *ctlr)
{
/*
* The controller may implement only the high-level SPI-memory like
* operations if it does not support regular SPI transfers, and this is
* valid use case.
* If ->mem_ops is NULL, we request that at least one of the
* ->transfer_xxx() method be implemented.
*/
if (ctlr->mem_ops) {
if (!ctlr->mem_ops->exec_op)
return -EINVAL;
} else if (!ctlr->transfer && !ctlr->transfer_one &&
!ctlr->transfer_one_message) {
return -EINVAL;
}
return 0;
}
/**
* spi_register_controller - register SPI master or slave controller
* @ctlr: initialized master, originally from spi_alloc_master() or
* spi_alloc_slave()
* Context: can sleep
*
* SPI controllers connect to their drivers using some non-SPI bus,
* such as the platform bus. The final stage of probe() in that code
* includes calling spi_register_controller() to hook up to this SPI bus glue.
*
* SPI controllers use board specific (often SOC specific) bus numbers,
* and board-specific addressing for SPI devices combines those numbers
* with chip select numbers. Since SPI does not directly support dynamic
* device identification, boards need configuration tables telling which
* chip is at which address.
*
* This must be called from context that can sleep. It returns zero on
* success, else a negative error code (dropping the controller's refcount).
* After a successful return, the caller is responsible for calling
* spi_unregister_controller().
*
* Return: zero on success, else a negative error code.
*/
int spi_register_controller(struct spi_controller *ctlr)
{
struct device *dev = ctlr->dev.parent;
struct boardinfo *bi;
int status;
int id, first_dynamic;
if (!dev)
return -ENODEV;
/*
* Make sure all necessary hooks are implemented before registering
* the SPI controller.
*/
status = spi_controller_check_ops(ctlr);
if (status)
return status;
if (ctlr->bus_num >= 0) {
/* devices with a fixed bus num must check-in with the num */
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
ctlr->bus_num + 1, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id == -ENOSPC ? -EBUSY : id;
ctlr->bus_num = id;
} else if (ctlr->dev.of_node) {
/* allocate dynamic bus number using Linux idr */
id = of_alias_get_id(ctlr->dev.of_node, "spi");
if (id >= 0) {
ctlr->bus_num = id;
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
ctlr->bus_num + 1, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id == -ENOSPC ? -EBUSY : id;
}
}
if (ctlr->bus_num < 0) {
first_dynamic = of_alias_get_highest_id("spi");
if (first_dynamic < 0)
first_dynamic = 0;
else
first_dynamic++;
mutex_lock(&board_lock);
id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
0, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id;
ctlr->bus_num = id;
}
INIT_LIST_HEAD(&ctlr->queue);
spin_lock_init(&ctlr->queue_lock);
spin_lock_init(&ctlr->bus_lock_spinlock);
mutex_init(&ctlr->bus_lock_mutex);
mutex_init(&ctlr->io_mutex);
ctlr->bus_lock_flag = 0;
init_completion(&ctlr->xfer_completion);
if (!ctlr->max_dma_len)
ctlr->max_dma_len = INT_MAX;
/* register the device, then userspace will see it.
* registration fails if the bus ID is in use.
*/
dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
if (!spi_controller_is_slave(ctlr)) {
if (ctlr->use_gpio_descriptors) {
status = spi_get_gpio_descs(ctlr);
if (status)
goto free_bus_id;
/*
* A controller using GPIO descriptors always
* supports SPI_CS_HIGH if need be.
*/
ctlr->mode_bits |= SPI_CS_HIGH;
} else {
/* Legacy code path for GPIOs from DT */
status = of_spi_get_gpio_numbers(ctlr);
if (status)
goto free_bus_id;
}
}
/*
* Even if it's just one always-selected device, there must
* be at least one chipselect.
*/
if (!ctlr->num_chipselect) {
status = -EINVAL;
goto free_bus_id;
}
status = device_add(&ctlr->dev);
if (status < 0)
goto free_bus_id;
dev_dbg(dev, "registered %s %s\n",
spi_controller_is_slave(ctlr) ? "slave" : "master",
dev_name(&ctlr->dev));
/*
* If we're using a queued driver, start the queue. Note that we don't
* need the queueing logic if the driver is only supporting high-level
* memory operations.
*/
if (ctlr->transfer) {
dev_info(dev, "controller is unqueued, this is deprecated\n");
} else if (ctlr->transfer_one || ctlr->transfer_one_message) {
status = spi_controller_initialize_queue(ctlr);
if (status) {
device_del(&ctlr->dev);
goto free_bus_id;
}
}
/* add statistics */
spin_lock_init(&ctlr->statistics.lock);
mutex_lock(&board_lock);
list_add_tail(&ctlr->list, &spi_controller_list);
list_for_each_entry(bi, &board_list, list)
spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
mutex_unlock(&board_lock);
/* Register devices from the device tree and ACPI */
of_register_spi_devices(ctlr);
acpi_register_spi_devices(ctlr);
return status;
free_bus_id:
mutex_lock(&board_lock);
idr_remove(&spi_master_idr, ctlr->bus_num);
mutex_unlock(&board_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_register_controller);
static void devm_spi_unregister(void *ctlr)
{
spi_unregister_controller(ctlr);
}
/**
* devm_spi_register_controller - register managed SPI master or slave
* controller
* @dev: device managing SPI controller
* @ctlr: initialized controller, originally from spi_alloc_master() or
* spi_alloc_slave()
* Context: can sleep
*
* Register a SPI device as with spi_register_controller() which will
* automatically be unregistered and freed.
*
* Return: zero on success, else a negative error code.
*/
int devm_spi_register_controller(struct device *dev,
struct spi_controller *ctlr)
{
int ret;
ret = spi_register_controller(ctlr);
if (ret)
return ret;
return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
}
EXPORT_SYMBOL_GPL(devm_spi_register_controller);
static int __unregister(struct device *dev, void *null)
{
spi_unregister_device(to_spi_device(dev));
return 0;
}
/**
* spi_unregister_controller - unregister SPI master or slave controller
* @ctlr: the controller being unregistered
* Context: can sleep
*
* This call is used only by SPI controller drivers, which are the
* only ones directly touching chip registers.
*
* This must be called from context that can sleep.
*
* Note that this function also drops a reference to the controller.
*/
void spi_unregister_controller(struct spi_controller *ctlr)
{
struct spi_controller *found;
int id = ctlr->bus_num;
/* Prevent addition of new devices, unregister existing ones */
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_lock(&spi_add_lock);
device_for_each_child(&ctlr->dev, NULL, __unregister);
/* First make sure that this controller was ever added */
mutex_lock(&board_lock);
found = idr_find(&spi_master_idr, id);
mutex_unlock(&board_lock);
if (ctlr->queued) {
if (spi_destroy_queue(ctlr))
dev_err(&ctlr->dev, "queue remove failed\n");
}
mutex_lock(&board_lock);
list_del(&ctlr->list);
mutex_unlock(&board_lock);
device_del(&ctlr->dev);
/* Release the last reference on the controller if its driver
* has not yet been converted to devm_spi_alloc_master/slave().
*/
if (!ctlr->devm_allocated)
put_device(&ctlr->dev);
/* free bus id */
mutex_lock(&board_lock);
if (found == ctlr)
idr_remove(&spi_master_idr, id);
mutex_unlock(&board_lock);
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_unlock(&spi_add_lock);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);
int spi_controller_suspend(struct spi_controller *ctlr)
{
int ret;
/* Basically no-ops for non-queued controllers */
if (!ctlr->queued)
return 0;
ret = spi_stop_queue(ctlr);
if (ret)
dev_err(&ctlr->dev, "queue stop failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_suspend);
int spi_controller_resume(struct spi_controller *ctlr)
{
int ret;
if (!ctlr->queued)
return 0;
ret = spi_start_queue(ctlr);
if (ret)
dev_err(&ctlr->dev, "queue restart failed\n");
return ret;
}
EXPORT_SYMBOL_GPL(spi_controller_resume);
static int __spi_controller_match(struct device *dev, const void *data)
{
struct spi_controller *ctlr;
const u16 *bus_num = data;
ctlr = container_of(dev, struct spi_controller, dev);
return ctlr->bus_num == *bus_num;
}
/**
* spi_busnum_to_master - look up master associated with bus_num
* @bus_num: the master's bus number
* Context: can sleep
*
* This call may be used with devices that are registered after
* arch init time. It returns a refcounted pointer to the relevant
* spi_controller (which the caller must release), or NULL if there is
* no such master registered.
*
* Return: the SPI master structure on success, else NULL.
*/
struct spi_controller *spi_busnum_to_master(u16 bus_num)
{
struct device *dev;
struct spi_controller *ctlr = NULL;
dev = class_find_device(&spi_master_class, NULL, &bus_num,
__spi_controller_match);
if (dev)
ctlr = container_of(dev, struct spi_controller, dev);
/* reference got in class_find_device */
return ctlr;
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);
/*-------------------------------------------------------------------------*/
/* Core methods for SPI resource management */
/**
* spi_res_alloc - allocate a spi resource that is life-cycle managed
* during the processing of a spi_message while using
* spi_transfer_one
* @spi: the spi device for which we allocate memory
* @release: the release code to execute for this resource
* @size: size to alloc and return
* @gfp: GFP allocation flags
*
* Return: the pointer to the allocated data
*
* This may get enhanced in the future to allocate from a memory pool
* of the @spi_device or @spi_controller to avoid repeated allocations.
*/
void *spi_res_alloc(struct spi_device *spi,
spi_res_release_t release,
size_t size, gfp_t gfp)
{
struct spi_res *sres;
sres = kzalloc(sizeof(*sres) + size, gfp);
if (!sres)
return NULL;
INIT_LIST_HEAD(&sres->entry);
sres->release = release;
return sres->data;
}
EXPORT_SYMBOL_GPL(spi_res_alloc);
/**
* spi_res_free - free an spi resource
* @res: pointer to the custom data of a resource
*
*/
void spi_res_free(void *res)
{
struct spi_res *sres = container_of(res, struct spi_res, data);
if (!res)
return;
WARN_ON(!list_empty(&sres->entry));
kfree(sres);
}
EXPORT_SYMBOL_GPL(spi_res_free);
/**
* spi_res_add - add a spi_res to the spi_message
* @message: the spi message
* @res: the spi_resource
*/
void spi_res_add(struct spi_message *message, void *res)
{
struct spi_res *sres = container_of(res, struct spi_res, data);
WARN_ON(!list_empty(&sres->entry));
list_add_tail(&sres->entry, &message->resources);
}
EXPORT_SYMBOL_GPL(spi_res_add);
/**
* spi_res_release - release all spi resources for this message
* @ctlr: the @spi_controller
* @message: the @spi_message
*/
void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
{
struct spi_res *res, *tmp;
list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
if (res->release)
res->release(ctlr, message, res->data);
list_del(&res->entry);
kfree(res);
}
}
EXPORT_SYMBOL_GPL(spi_res_release);
/*-------------------------------------------------------------------------*/
/* Core methods for spi_message alterations */
static void __spi_replace_transfers_release(struct spi_controller *ctlr,
struct spi_message *msg,
void *res)
{
struct spi_replaced_transfers *rxfer = res;
size_t i;
/* call extra callback if requested */
if (rxfer->release)
rxfer->release(ctlr, msg, res);
/* insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
/* remove the formerly inserted entries */
for (i = 0; i < rxfer->inserted; i++)
list_del(&rxfer->inserted_transfers[i].transfer_list);
}
/**
* spi_replace_transfers - replace transfers with several transfers
* and register change with spi_message.resources
* @msg: the spi_message we work upon
* @xfer_first: the first spi_transfer we want to replace
* @remove: number of transfers to remove
* @insert: the number of transfers we want to insert instead
* @release: extra release code necessary in some circumstances
* @extradatasize: extra data to allocate (with alignment guarantees
* of struct @spi_transfer)
* @gfp: gfp flags
*
* Returns: pointer to @spi_replaced_transfers,
* PTR_ERR(...) in case of errors.
*/
struct spi_replaced_transfers *spi_replace_transfers(
struct spi_message *msg,
struct spi_transfer *xfer_first,
size_t remove,
size_t insert,
spi_replaced_release_t release,
size_t extradatasize,
gfp_t gfp)
{
struct spi_replaced_transfers *rxfer;
struct spi_transfer *xfer;
size_t i;
/* allocate the structure using spi_res */
rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
struct_size(rxfer, inserted_transfers, insert)
+ extradatasize,
gfp);
if (!rxfer)
return ERR_PTR(-ENOMEM);
/* the release code to invoke before running the generic release */
rxfer->release = release;
/* assign extradata */
if (extradatasize)
rxfer->extradata =
&rxfer->inserted_transfers[insert];
/* init the replaced_transfers list */
INIT_LIST_HEAD(&rxfer->replaced_transfers);
/* assign the list_entry after which we should reinsert
* the @replaced_transfers - it may be spi_message.messages!
*/
rxfer->replaced_after = xfer_first->transfer_list.prev;
/* remove the requested number of transfers */
for (i = 0; i < remove; i++) {
/* if the entry after replaced_after it is msg->transfers
* then we have been requested to remove more transfers
* than are in the list
*/
if (rxfer->replaced_after->next == &msg->transfers) {
dev_err(&msg->spi->dev,
"requested to remove more spi_transfers than are available\n");
/* insert replaced transfers back into the message */
list_splice(&rxfer->replaced_transfers,
rxfer->replaced_after);
/* free the spi_replace_transfer structure */
spi_res_free(rxfer);
/* and return with an error */
return ERR_PTR(-EINVAL);
}
/* remove the entry after replaced_after from list of
* transfers and add it to list of replaced_transfers
*/
list_move_tail(rxfer->replaced_after->next,
&rxfer->replaced_transfers);
}
/* create copy of the given xfer with identical settings
* based on the first transfer to get removed
*/
for (i = 0; i < insert; i++) {
/* we need to run in reverse order */
xfer = &rxfer->inserted_transfers[insert - 1 - i];
/* copy all spi_transfer data */
memcpy(xfer, xfer_first, sizeof(*xfer));
/* add to list */
list_add(&xfer->transfer_list, rxfer->replaced_after);
/* clear cs_change and delay for all but the last */
if (i) {
xfer->cs_change = false;
xfer->delay.value = 0;
}
}
/* set up inserted */
rxfer->inserted = insert;
/* and register it with spi_res/spi_message */
spi_res_add(msg, rxfer);
return rxfer;
}
EXPORT_SYMBOL_GPL(spi_replace_transfers);
static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
struct spi_message *msg,
struct spi_transfer **xferp,
size_t maxsize,
gfp_t gfp)
{
struct spi_transfer *xfer = *xferp, *xfers;
struct spi_replaced_transfers *srt;
size_t offset;
size_t count, i;
/* calculate how many we have to replace */
count = DIV_ROUND_UP(xfer->len, maxsize);
/* create replacement */
srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
if (IS_ERR(srt))
return PTR_ERR(srt);
xfers = srt->inserted_transfers;
/* now handle each of those newly inserted spi_transfers
* note that the replacements spi_transfers all are preset
* to the same values as *xferp, so tx_buf, rx_buf and len
* are all identical (as well as most others)
* so we just have to fix up len and the pointers.
*
* this also includes support for the depreciated
* spi_message.is_dma_mapped interface
*/
/* the first transfer just needs the length modified, so we
* run it outside the loop
*/
xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
/* all the others need rx_buf/tx_buf also set */
for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
/* update rx_buf, tx_buf and dma */
if (xfers[i].rx_buf)
xfers[i].rx_buf += offset;
if (xfers[i].rx_dma)
xfers[i].rx_dma += offset;
if (xfers[i].tx_buf)
xfers[i].tx_buf += offset;
if (xfers[i].tx_dma)
xfers[i].tx_dma += offset;
/* update length */
xfers[i].len = min(maxsize, xfers[i].len - offset);
}
/* we set up xferp to the last entry we have inserted,
* so that we skip those already split transfers
*/
*xferp = &xfers[count - 1];
/* increment statistics counters */
SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
transfers_split_maxsize);
SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
transfers_split_maxsize);
return 0;
}
/**
* spi_split_transfers_maxsize - split spi transfers into multiple transfers
* when an individual transfer exceeds a
* certain size
* @ctlr: the @spi_controller for this transfer
* @msg: the @spi_message to transform
* @maxsize: the maximum when to apply this
* @gfp: GFP allocation flags
*
* Return: status of transformation
*/
int spi_split_transfers_maxsize(struct spi_controller *ctlr,
struct spi_message *msg,
size_t maxsize,
gfp_t gfp)
{
struct spi_transfer *xfer;
int ret;
/* iterate over the transfer_list,
* but note that xfer is advanced to the last transfer inserted
* to avoid checking sizes again unnecessarily (also xfer does
* potentiall belong to a different list by the time the
* replacement has happened
*/
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (xfer->len > maxsize) {
ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
maxsize, gfp);
if (ret)
return ret;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
/*-------------------------------------------------------------------------*/
/* Core methods for SPI controller protocol drivers. Some of the
* other core methods are currently defined as inline functions.
*/
static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
u8 bits_per_word)
{
if (ctlr->bits_per_word_mask) {
/* Only 32 bits fit in the mask */
if (bits_per_word > 32)
return -EINVAL;
if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
return -EINVAL;
}
return 0;
}
/**
* spi_setup - setup SPI mode and clock rate
* @spi: the device whose settings are being modified
* Context: can sleep, and no requests are queued to the device
*
* SPI protocol drivers may need to update the transfer mode if the
* device doesn't work with its default. They may likewise need
* to update clock rates or word sizes from initial values. This function
* changes those settings, and must be called from a context that can sleep.
* Except for SPI_CS_HIGH, which takes effect immediately, the changes take
* effect the next time the device is selected and data is transferred to
* or from it. When this function returns, the spi device is deselected.
*
* Note that this call will fail if the protocol driver specifies an option
* that the underlying controller or its driver does not support. For
* example, not all hardware supports wire transfers using nine bit words,
* LSB-first wire encoding, or active-high chipselects.
*
* Return: zero on success, else a negative error code.
*/
int spi_setup(struct spi_device *spi)
{
unsigned bad_bits, ugly_bits;
int status;
/*
* check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
* are set at the same time
*/
if ((hweight_long(spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
(hweight_long(spi->mode &
(SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
dev_err(&spi->dev,
"setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
return -EINVAL;
}
/* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
*/
if ((spi->mode & SPI_3WIRE) && (spi->mode &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
return -EINVAL;
/* help drivers fail *cleanly* when they need options
* that aren't supported with their current controller
* SPI_CS_WORD has a fallback software implementation,
* so it is ignored here.
*/
bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
SPI_NO_TX | SPI_NO_RX);
/* nothing prevents from working with active-high CS in case if it
* is driven by GPIO.
*/
if (gpio_is_valid(spi->cs_gpio))
bad_bits &= ~SPI_CS_HIGH;
ugly_bits = bad_bits &
(SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
if (ugly_bits) {
dev_warn(&spi->dev,
"setup: ignoring unsupported mode bits %x\n",
ugly_bits);
spi->mode &= ~ugly_bits;
bad_bits &= ~ugly_bits;
}
if (bad_bits) {
dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
bad_bits);
return -EINVAL;
}
if (!spi->bits_per_word)
spi->bits_per_word = 8;
status = __spi_validate_bits_per_word(spi->controller,
spi->bits_per_word);
if (status)
return status;
if (spi->controller->max_speed_hz &&
(!spi->max_speed_hz ||
spi->max_speed_hz > spi->controller->max_speed_hz))
spi->max_speed_hz = spi->controller->max_speed_hz;
mutex_lock(&spi->controller->io_mutex);
if (spi->controller->setup) {
status = spi->controller->setup(spi);
if (status) {
mutex_unlock(&spi->controller->io_mutex);
dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
status);
return status;
}
}
if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
status = pm_runtime_get_sync(spi->controller->dev.parent);
if (status < 0) {
mutex_unlock(&spi->controller->io_mutex);
pm_runtime_put_noidle(spi->controller->dev.parent);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status);
return status;
}
/*
* We do not want to return positive value from pm_runtime_get,
* there are many instances of devices calling spi_setup() and
* checking for a non-zero return value instead of a negative
* return value.
*/
status = 0;
spi_set_cs(spi, false, true);
pm_runtime_mark_last_busy(spi->controller->dev.parent);
pm_runtime_put_autosuspend(spi->controller->dev.parent);
} else {
spi_set_cs(spi, false, true);
}
mutex_unlock(&spi->controller->io_mutex);
if (spi->rt && !spi->controller->rt) {
spi->controller->rt = true;
spi_set_thread_rt(spi->controller);
}
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
(spi->mode & SPI_3WIRE) ? "3wire, " : "",
(spi->mode & SPI_LOOP) ? "loopback, " : "",
spi->bits_per_word, spi->max_speed_hz,
status);
return status;
}
EXPORT_SYMBOL_GPL(spi_setup);
/**
* spi_set_cs_timing - configure CS setup, hold, and inactive delays
* @spi: the device that requires specific CS timing configuration
* @setup: CS setup time specified via @spi_delay
* @hold: CS hold time specified via @spi_delay
* @inactive: CS inactive delay between transfers specified via @spi_delay
*
* Return: zero on success, else a negative error code.
*/
int spi_set_cs_timing(struct spi_device *spi, struct spi_delay *setup,
struct spi_delay *hold, struct spi_delay *inactive)
{
struct device *parent = spi->controller->dev.parent;
size_t len;
int status;
if (spi->controller->set_cs_timing &&
!(spi->cs_gpiod || gpio_is_valid(spi->cs_gpio))) {
mutex_lock(&spi->controller->io_mutex);
if (spi->controller->auto_runtime_pm) {
status = pm_runtime_get_sync(parent);
if (status < 0) {
mutex_unlock(&spi->controller->io_mutex);
pm_runtime_put_noidle(parent);
dev_err(&spi->controller->dev, "Failed to power device: %d\n",
status);
return status;
}
status = spi->controller->set_cs_timing(spi, setup,
hold, inactive);
pm_runtime_mark_last_busy(parent);
pm_runtime_put_autosuspend(parent);
} else {
status = spi->controller->set_cs_timing(spi, setup, hold,
inactive);
}
mutex_unlock(&spi->controller->io_mutex);
return status;
}
if ((setup && setup->unit == SPI_DELAY_UNIT_SCK) ||
(hold && hold->unit == SPI_DELAY_UNIT_SCK) ||
(inactive && inactive->unit == SPI_DELAY_UNIT_SCK)) {
dev_err(&spi->dev,
"Clock-cycle delays for CS not supported in SW mode\n");
return -ENOTSUPP;
}
len = sizeof(struct spi_delay);
/* copy delays to controller */
if (setup)
memcpy(&spi->controller->cs_setup, setup, len);
else
memset(&spi->controller->cs_setup, 0, len);
if (hold)
memcpy(&spi->controller->cs_hold, hold, len);
else
memset(&spi->controller->cs_hold, 0, len);
if (inactive)
memcpy(&spi->controller->cs_inactive, inactive, len);
else
memset(&spi->controller->cs_inactive, 0, len);
return 0;
}
EXPORT_SYMBOL_GPL(spi_set_cs_timing);
static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
struct spi_device *spi)
{
int delay1, delay2;
delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
if (delay1 < 0)
return delay1;
delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
if (delay2 < 0)
return delay2;
if (delay1 < delay2)
memcpy(&xfer->word_delay, &spi->word_delay,
sizeof(xfer->word_delay));
return 0;
}
static int __spi_validate(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
struct spi_transfer *xfer;
int w_size;
if (list_empty(&message->transfers))
return -EINVAL;
/* If an SPI controller does not support toggling the CS line on each
* transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
* for the CS line, we can emulate the CS-per-word hardware function by
* splitting transfers into one-word transfers and ensuring that
* cs_change is set for each transfer.
*/
if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
spi->cs_gpiod ||
gpio_is_valid(spi->cs_gpio))) {
size_t maxsize;
int ret;
maxsize = (spi->bits_per_word + 7) / 8;
/* spi_split_transfers_maxsize() requires message->spi */
message->spi = spi;
ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
GFP_KERNEL);
if (ret)
return ret;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
/* don't change cs_change on the last entry in the list */
if (list_is_last(&xfer->transfer_list, &message->transfers))
break;
xfer->cs_change = 1;
}
}
/* Half-duplex links include original MicroWire, and ones with
* only one data pin like SPI_3WIRE (switches direction) or where
* either MOSI or MISO is missing. They can also be caused by
* software limitations.
*/
if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
(spi->mode & SPI_3WIRE)) {
unsigned flags = ctlr->flags;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
if (xfer->rx_buf && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
return -EINVAL;
if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
return -EINVAL;
}
}
/**
* Set transfer bits_per_word and max speed as spi device default if
* it is not set for this transfer.
* Set transfer tx_nbits and rx_nbits as single transfer default
* (SPI_NBITS_SINGLE) if it is not set for this transfer.
* Ensure transfer word_delay is at least as long as that required by
* device itself.
*/
message->frame_length = 0;
list_for_each_entry(xfer, &message->transfers, transfer_list) {
xfer->effective_speed_hz = 0;
message->frame_length += xfer->len;
if (!xfer->bits_per_word)
xfer->bits_per_word = spi->bits_per_word;
if (!xfer->speed_hz)
xfer->speed_hz = spi->max_speed_hz;
if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
xfer->speed_hz = ctlr->max_speed_hz;
if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
return -EINVAL;
/*
* SPI transfer length should be multiple of SPI word size
* where SPI word size should be power-of-two multiple
*/
if (xfer->bits_per_word <= 8)
w_size = 1;
else if (xfer->bits_per_word <= 16)
w_size = 2;
else
w_size = 4;
/* No partial transfers accepted */
if (xfer->len % w_size)
return -EINVAL;
if (xfer->speed_hz && ctlr->min_speed_hz &&
xfer->speed_hz < ctlr->min_speed_hz)
return -EINVAL;
if (xfer->tx_buf && !xfer->tx_nbits)
xfer->tx_nbits = SPI_NBITS_SINGLE;
if (xfer->rx_buf && !xfer->rx_nbits)
xfer->rx_nbits = SPI_NBITS_SINGLE;
/* check transfer tx/rx_nbits:
* 1. check the value matches one of single, dual and quad
* 2. check tx/rx_nbits match the mode in spi_device
*/
if (xfer->tx_buf) {
if (spi->mode & SPI_NO_TX)
return -EINVAL;
if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
xfer->tx_nbits != SPI_NBITS_DUAL &&
xfer->tx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
return -EINVAL;
if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_TX_QUAD))
return -EINVAL;
}
/* check transfer rx_nbits */
if (xfer->rx_buf) {
if (spi->mode & SPI_NO_RX)
return -EINVAL;
if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
xfer->rx_nbits != SPI_NBITS_DUAL &&
xfer->rx_nbits != SPI_NBITS_QUAD)
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
!(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
return -EINVAL;
if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
!(spi->mode & SPI_RX_QUAD))
return -EINVAL;
}
if (_spi_xfer_word_delay_update(xfer, spi))
return -EINVAL;
}
message->status = -EINPROGRESS;
return 0;
}
static int __spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
struct spi_transfer *xfer;
/*
* Some controllers do not support doing regular SPI transfers. Return
* ENOTSUPP when this is the case.
*/
if (!ctlr->transfer)
return -ENOTSUPP;
message->spi = spi;
SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
trace_spi_message_submit(message);
if (!ctlr->ptp_sts_supported) {
list_for_each_entry(xfer, &message->transfers, transfer_list) {
xfer->ptp_sts_word_pre = 0;
ptp_read_system_prets(xfer->ptp_sts);
}
}
return ctlr->transfer(spi, message);
}
/**
* spi_async - asynchronous SPI transfer
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*
* Return: zero on success, else a negative error code.
*/
int spi_async(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
int ret;
unsigned long flags;
ret = __spi_validate(spi, message);
if (ret != 0)
return ret;
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
if (ctlr->bus_lock_flag)
ret = -EBUSY;
else
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(spi_async);
/**
* spi_async_locked - version of spi_async with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers, including completion callback
* Context: any (irqs may be blocked, etc)
*
* This call may be used in_irq and other contexts which can't sleep,
* as well as from task contexts which can sleep.
*
* The completion callback is invoked in a context which can't sleep.
* Before that invocation, the value of message->status is undefined.
* When the callback is issued, message->status holds either zero (to
* indicate complete success) or a negative error code. After that
* callback returns, the driver which issued the transfer request may
* deallocate the associated memory; it's no longer in use by any SPI
* core or controller driver code.
*
* Note that although all messages to a spi_device are handled in
* FIFO order, messages may go to different devices in other orders.
* Some device might be higher priority, or have various "hard" access
* time requirements, for example.
*
* On detection of any fault during the transfer, processing of
* the entire message is aborted, and the device is deselected.
* Until returning from the associated message completion callback,
* no other spi_message queued to that device will be processed.
* (This rule applies equally to all the synchronous transfer calls,
* which are wrappers around this core asynchronous primitive.)
*
* Return: zero on success, else a negative error code.
*/
int spi_async_locked(struct spi_device *spi, struct spi_message *message)
{
struct spi_controller *ctlr = spi->controller;
int ret;
unsigned long flags;
ret = __spi_validate(spi, message);
if (ret != 0)
return ret;
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
ret = __spi_async(spi, message);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(spi_async_locked);
/*-------------------------------------------------------------------------*/
/* Utility methods for SPI protocol drivers, layered on
* top of the core. Some other utility methods are defined as
* inline functions.
*/
static void spi_complete(void *arg)
{
complete(arg);
}
static int __spi_sync(struct spi_device *spi, struct spi_message *message)
{
DECLARE_COMPLETION_ONSTACK(done);
int status;
struct spi_controller *ctlr = spi->controller;
unsigned long flags;
status = __spi_validate(spi, message);
if (status != 0)
return status;
message->complete = spi_complete;
message->context = &done;
message->spi = spi;
SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
/* If we're not using the legacy transfer method then we will
* try to transfer in the calling context so special case.
* This code would be less tricky if we could remove the
* support for driver implemented message queues.
*/
if (ctlr->transfer == spi_queued_transfer) {
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
trace_spi_message_submit(message);
status = __spi_queued_transfer(spi, message, false);
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
} else {
status = spi_async_locked(spi, message);
}
if (status == 0) {
/* Push out the messages in the calling context if we
* can.
*/
if (ctlr->transfer == spi_queued_transfer) {
SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
spi_sync_immediate);
SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
spi_sync_immediate);
__spi_pump_messages(ctlr, false);
}
wait_for_completion(&done);
status = message->status;
}
message->context = NULL;
return status;
}
/**
* spi_sync - blocking/synchronous SPI data transfers
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* Note that the SPI device's chip select is active during the message,
* and then is normally disabled between messages. Drivers for some
* frequently-used devices may want to minimize costs of selecting a chip,
* by leaving it selected in anticipation that the next message will go
* to the same chip. (That may increase power usage.)
*
* Also, the caller is guaranteeing that the memory associated with the
* message will not be freed before this call returns.
*
* Return: zero on success, else a negative error code.
*/
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
int ret;
mutex_lock(&spi->controller->bus_lock_mutex);
ret = __spi_sync(spi, message);
mutex_unlock(&spi->controller->bus_lock_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(spi_sync);
/**
* spi_sync_locked - version of spi_sync with exclusive bus usage
* @spi: device with which data will be exchanged
* @message: describes the data transfers
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout. Low-overhead controller
* drivers may DMA directly into and out of the message buffers.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
* be released by a spi_bus_unlock call when the exclusive access is over.
*
* Return: zero on success, else a negative error code.
*/
int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
{
return __spi_sync(spi, message);
}
EXPORT_SYMBOL_GPL(spi_sync_locked);
/**
* spi_bus_lock - obtain a lock for exclusive SPI bus usage
* @ctlr: SPI bus master that should be locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call should be used by drivers that require exclusive access to the
* SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
* exclusive access is over. Data transfer must be done by spi_sync_locked
* and spi_async_locked calls when the SPI bus lock is held.
*
* Return: always zero.
*/
int spi_bus_lock(struct spi_controller *ctlr)
{
unsigned long flags;
mutex_lock(&ctlr->bus_lock_mutex);
spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
ctlr->bus_lock_flag = 1;
spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
/* mutex remains locked until spi_bus_unlock is called */
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_lock);
/**
* spi_bus_unlock - release the lock for exclusive SPI bus usage
* @ctlr: SPI bus master that was locked for exclusive bus access
* Context: can sleep
*
* This call may only be used from a context that may sleep. The sleep
* is non-interruptible, and has no timeout.
*
* This call releases an SPI bus lock previously obtained by an spi_bus_lock
* call.
*
* Return: always zero.
*/
int spi_bus_unlock(struct spi_controller *ctlr)
{
ctlr->bus_lock_flag = 0;
mutex_unlock(&ctlr->bus_lock_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spi_bus_unlock);
/* portable code must never pass more than 32 bytes */
#define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
static u8 *buf;
/**
* spi_write_then_read - SPI synchronous write followed by read
* @spi: device with which data will be exchanged
* @txbuf: data to be written (need not be dma-safe)
* @n_tx: size of txbuf, in bytes
* @rxbuf: buffer into which data will be read (need not be dma-safe)
* @n_rx: size of rxbuf, in bytes
* Context: can sleep
*
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* is zero for success, else a negative errno status code.
* This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer.
* Performance-sensitive or bulk transfer code should instead use
* spi_{async,sync}() calls with dma-safe buffers.
*
* Return: zero on success, else a negative error code.
*/
int spi_write_then_read(struct spi_device *spi,
const void *txbuf, unsigned n_tx,
void *rxbuf, unsigned n_rx)
{
static DEFINE_MUTEX(lock);
int status;
struct spi_message message;
struct spi_transfer x[2];
u8 *local_buf;
/* Use preallocated DMA-safe buffer if we can. We can't avoid
* copying here, (as a pure convenience thing), but we can
* keep heap costs out of the hot path unless someone else is
* using the pre-allocated buffer or the transfer is too large.
*/
if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
GFP_KERNEL | GFP_DMA);
if (!local_buf)
return -ENOMEM;
} else {
local_buf = buf;
}
spi_message_init(&message);
memset(x, 0, sizeof(x));
if (n_tx) {
x[0].len = n_tx;
spi_message_add_tail(&x[0], &message);
}
if (n_rx) {
x[1].len = n_rx;
spi_message_add_tail(&x[1], &message);
}
memcpy(local_buf, txbuf, n_tx);
x[0].tx_buf = local_buf;
x[1].rx_buf = local_buf + n_tx;
/* do the i/o */
status = spi_sync(spi, &message);
if (status == 0)
memcpy(rxbuf, x[1].rx_buf, n_rx);
if (x[0].tx_buf == buf)
mutex_unlock(&lock);
else
kfree(local_buf);
return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);
/*-------------------------------------------------------------------------*/
#if IS_ENABLED(CONFIG_OF)
/* must call put_device() when done with returned spi_device device */
struct spi_device *of_find_spi_device_by_node(struct device_node *node)
{
struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
return dev ? to_spi_device(dev) : NULL;
}
EXPORT_SYMBOL_GPL(of_find_spi_device_by_node);
#endif /* IS_ENABLED(CONFIG_OF) */
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
/* the spi controllers are not using spi_bus, so we find it with another way */
static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
{
struct device *dev;
dev = class_find_device_by_of_node(&spi_master_class, node);
if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device_by_of_node(&spi_slave_class, node);
if (!dev)
return NULL;
/* reference got in class_find_device */
return container_of(dev, struct spi_controller, dev);
}
static int of_spi_notify(struct notifier_block *nb, unsigned long action,
void *arg)
{
struct of_reconfig_data *rd = arg;
struct spi_controller *ctlr;
struct spi_device *spi;
switch (of_reconfig_get_state_change(action, arg)) {
case OF_RECONFIG_CHANGE_ADD:
ctlr = of_find_spi_controller_by_node(rd->dn->parent);
if (ctlr == NULL)
return NOTIFY_OK; /* not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
put_device(&ctlr->dev);
return NOTIFY_OK;
}
spi = of_register_spi_device(ctlr, rd->dn);
put_device(&ctlr->dev);
if (IS_ERR(spi)) {
pr_err("%s: failed to create for '%pOF'\n",
__func__, rd->dn);
of_node_clear_flag(rd->dn, OF_POPULATED);
return notifier_from_errno(PTR_ERR(spi));
}
break;
case OF_RECONFIG_CHANGE_REMOVE:
/* already depopulated? */
if (!of_node_check_flag(rd->dn, OF_POPULATED))
return NOTIFY_OK;
/* find our device by node */
spi = of_find_spi_device_by_node(rd->dn);
if (spi == NULL)
return NOTIFY_OK; /* no? not meant for us */
/* unregister takes one ref away */
spi_unregister_device(spi);
/* and put the reference of the find */
put_device(&spi->dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block spi_of_notifier = {
.notifier_call = of_spi_notify,
};
#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
extern struct notifier_block spi_of_notifier;
#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
#if IS_ENABLED(CONFIG_ACPI)
static int spi_acpi_controller_match(struct device *dev, const void *data)
{
return ACPI_COMPANION(dev->parent) == data;
}
static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = class_find_device(&spi_master_class, NULL, adev,
spi_acpi_controller_match);
if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
dev = class_find_device(&spi_slave_class, NULL, adev,
spi_acpi_controller_match);
if (!dev)
return NULL;
return container_of(dev, struct spi_controller, dev);
}
static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
return to_spi_device(dev);
}
static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
void *arg)
{
struct acpi_device *adev = arg;
struct spi_controller *ctlr;
struct spi_device *spi;
switch (value) {
case ACPI_RECONFIG_DEVICE_ADD:
ctlr = acpi_spi_find_controller_by_adev(adev->parent);
if (!ctlr)
break;
acpi_register_spi_device(ctlr, adev);
put_device(&ctlr->dev);
break;
case ACPI_RECONFIG_DEVICE_REMOVE:
if (!acpi_device_enumerated(adev))
break;
spi = acpi_spi_find_device_by_adev(adev);
if (!spi)
break;
spi_unregister_device(spi);
put_device(&spi->dev);
break;
}
return NOTIFY_OK;
}
static struct notifier_block spi_acpi_notifier = {
.notifier_call = acpi_spi_notify,
};
#else
extern struct notifier_block spi_acpi_notifier;
#endif
static int __init spi_init(void)
{
int status;
buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
if (!buf) {
status = -ENOMEM;
goto err0;
}
status = bus_register(&spi_bus_type);
if (status < 0)
goto err1;
status = class_register(&spi_master_class);
if (status < 0)
goto err2;
if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
status = class_register(&spi_slave_class);
if (status < 0)
goto err3;
}
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
return 0;
err3:
class_unregister(&spi_master_class);
err2:
bus_unregister(&spi_bus_type);
err1:
kfree(buf);
buf = NULL;
err0:
return status;
}
/* board_info is normally registered in arch_initcall(),
* but even essential drivers wait till later
*
* REVISIT only boardinfo really needs static linking. the rest (device and
* driver registration) _could_ be dynamically linked (modular) ... costs
* include needing to have boardinfo data structures be much more public.
*/
postcore_initcall(spi_init);
Reference in New Issue View Git Blame Copy Permalink